#TRANSISTOR #WORKINGOFTRANSISTROR #PNP_NPN_TRANSISTOR #TRANSISTOR_AS_AMPLIFIER #BJT_UJT_FET_MOSFET_TRANSISTOR #TRANSISTOR_BIASING #TRANSISTOR_IN_HINDI #APPLICAION_OF_TRANSISTOR #VICHARACTERISTICSOFPNJUNCTIONDIODEINHINDIहिंदी #DIODECHARECTERISTICS #PN_DIODE_IN_HINDI #FORWARD_REVERSE_BIASED_DIODE #PN_JUNCTION_DIODE #PNJUNCTIONDIODEUNACADEMY #SEMINCONDUCTORDIODEINHINDI #BASICELECTRICALELECTRONICSENGINEERING #BEEE #RGPV #SAIACADEMYOFELECTRICALENGINEERING #SAEE #ELECTRONICSEMICONDUCTORDEVICE #EDC #ADC #GATE #IES #SSCJE #RRB #NTPC #BHEL #interviewelectricalengineering

1. Basic Electrical Engineering
PNP-NPN TRANSISTOR
CONSTRUCTION
WORKINGProf.Prasant Tiwari

2.  The word Transistor stands for Transfer of Resistor .
 It is current controlled device. It has many types, of which BJT is one.
 BJT is broadly classified into 2 types NPN and PNP .
 The main function of BJT Transistor is amplification.
 The small amount of base current controlled both the emitter and collector current.
 The transistor has two crystal diodes connected back to back.
 The left side of the diode in known as the emitter-base diode and the right side of the
diode is known as the collector-base diode.
TRANSISTOR DEFINITION

3.  The transistor in which one n-type material is doped
with two p-type materials such type of transistor is
known as PNP transistor.
 It is a current controlled device. The small amount of
base current controlled both the emitter and
collector current.
 The hole is the majority carriers of the PNP
transistors which constitute the current in it.
 The current inside the transistor is constituted
because of the changing position of holes and in the
leads of the transistor.
 It is because of the flow of the electrons. The PNP
transistor turns on when a small current flows
through the base.
 The direction of current in PNP transistor is from the
emitter to collector.
PNP TRANSISTOR
P
N
P
CONSTRUCTION

4. WORKING OF PNP TRANSISTOR
 The emitter-base junction is connected in forward biased due to which the emitter
pushes the holes in the base region.
 These holes constitute the emitter current. When these holes move into the N-type
semiconductor material or base, they combined with the electrons.
 The base of the transistor is thin and very lightly doped. Hence only a few holes
combined with the electrons and the remaining are moved towards the collector space
charge layer. Hence develops the base current.

5. NPN TRANSISTOR
 The transistor in which one p-type material is placed
between two n-type materials is known as NPN
transistor.
 The NPN transistor amplifies the weak signal enter into
the base and produces strong amplify signals at the
collector end.
 In NPN transistor, the direction of movement of an
electron is from the emitter to collector region due to
which the current constitutes in the transistor.
 Such type of transistor is mostly used in the circuit
because their majority charge carriers are electrons which
have high mobility as compared to holes.
 The NPN transistor has two diodes connected back to
back.
 The diode on the left side is called an emitter-base diode,
and the diodes on the right side are called collector-base
diode.

6. WORKING OFNPN TRANSISTOR
 The forward biased is applied across the emitter-base junction, and the reversed biased
is applied across the collector-base junction. The forward biased voltage VEB is small as
compared to the reverse bias voltage VCB.
 The emitter of the NPN transistor is heavily doped. When the forward bias is applied
across the emitter, the majority charge carriers move towards the base. This causes the
emitter current IE. The electrons enter into the P-type material and combine with the
holes.
 The base of the NPN transistor is lightly doped. Due to which only a few electrons are
combined and remaining constitutes the base current IB.

7. PLZ VISIT YPUTUBE CHANNEL FOR VIDEO
LINK IS GIVEN IN DESCRIPTION BOX